Answer:
I think they are all correct
No, work is not done whenever you hold a heavy object for a long time
<h3>What is work done ?</h3>
The result of a force's displacement and its component of force exerted by the object in the direction of displacement is what is known as the force's work. When we push a block with some force, the body moves quickly and work is completed.
- No work, as that term is used here, is done until the object is moved in some way and a component of the force travels along the path that the object is moved. Because there is no displacement when holding a heavy object still, energy is not transferred to it.
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Answer: The correct option is 2.
Explanation: Polyatomic ions are defined as the ions in which two or more elements are covalently bonded to act as a single unit. They always carry some charge.
Examples of polyatomic ions are: 
known as hydroxide ion, 
known as sulfate ion
We are given a compound 
having 2 ions which are 
and 
. these ions are named as sodium ions and hydrogen carbonate ions.
Therefore, the correct option is 2.
Remember, OIL RIG
Oxygen Is Loss of electrons
Reduction Is Gain of electrons
If something goes from + to - then it has gained electrons
If something goes from neutral to - it has gained electrons
If it goes from - to + is loses electrons
If it goes from neutral to + it loses electrons
If something is oxidised, it is a reducing agent
If something is reduced, it is an oxidising agent
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The blueprint process
The best known is a process using ammonium ferric citrate and potassium . The paper is impregnated with a solution of ammonium ferric citr
